Conservative groups ready to back Cotton's bid

The Club for Growth's political action committee on Wednesday endorsed Cotton, while the Senate Conservatives Fund said it's open to supporting the first-term congressman's Senate bid. Cotton announced Tuesday he was running against Pryor.

Pryor is seeking a third term and is widely viewed by the GOP as the most vulnerable Senate incumbent on the ballot in 2014. Cotton is the first Republican to announce he was running for Pryor's seat.

Both groups aired television ads criticizing Pryor before Cotton joined the race.